An apparently unrecognized disorder has been encountered in 14 patients, comprising brawny edema of the legs, migraine-like headaches, and a tendency to faint in the upright posture, associated with severe reduction in pulse pressure and acceleration of heart rate upright. Preliminary observations have shown that plasma bradykinin concentrations were consistently elevated above normal limits in 9 of 11 patients studied. It is proposed to determine the effects of factors which are known to aggravate the disorder and of treatments which have been found to ameliorate the symptoms on plasma levels of bradykinin, kallikrein and bradykininase. It is hoped that the proposed studies will serve to clarify the pathogenesis and lead to improved treatment of this incapacitating disorder.